Simultaneous actuator for snap switches



g- 1962 R. N. BOOTH ETAL smuumumous ACTUATOR FOR SNAP swxwcmas Filed April 27, 1955 INVENTORS RUSSELL N. BOOTH MARVNE. RUSSELL United States Patent 3,050,600 SIMULTANEOUS ACTUATOR FOR SNAP SWITCHES Russell N. Booth, Lakeville, and Marvin E. Russell, St. Louis Park, Minn, assiguors to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware lFiled Apr. 27, 1955, Ser. No. 504,170 2 Claims. (Cl. 200-814) This invention relates to snap switch actuators and more particularly to the simultaneous actuation of two or more snap switches.

One embodiment of our invention utilizes the simultaneous actuation of two unitary snap switches to change over heating and cooling circuits of unit air conditioners. The use of the two snap switches results in double pole double throw switching. Our invention provides this simultaneous snap action of two snap switches by securing a resilient plate to the usual switch actuating arm of a control device with the resilient plate extending over the plungers of two snap switches mounted side by side in the instrument frame. Thus the energy is built up in the plate before either switch snaps, and when one switch snaps the outward force on that plunger decreases so that the plate exerts greater force on the plunger of the other switch causing it to snap also. The reverse operation is similar except that energy is added to the plate as the switches snap.

Therefore, an object of our invention is to provide simultaneous action of two or more snap switches.

Another object of our invention is to provide positive simultaneous action of both of a pair of snap switches for a single given condition.

Further objects of our invention will become evident upon inspection of the following drawings, specification and claims.

FIGURE 1 is a plan view partially in section seen from the top of an embodiment of our invention with the casing removed.

- FIGURE 2 is an elevation partly in section of the embodiment of FIGURE 1.

FIGURE 3 is a fragmentary end view of another embodiment of our invention showning the cooperation of the switch plungers and a resilient plate.

In the drawings a frame has upwardly extending end portions 11 and 12 and a top portion 13. A cupshaped chamber 17 is" secured to the frame 10 by screws 18 and in conjunction with a cap-shaped diaphragm 19 forms an expansible chamber whose volume may be changed by varying the amount of fluid admitted between the diaphragm and the chamber. The diaphragm 19 is jointed to the chamber 17 at its periphery in any suitable manner such as by seam welding. While the diaphragm 19 has been illustrated as of plain cup-shaped configuration, it may be corrugated in a way to increase its flexibility. The chamber 17 is connetced to a sensing bulb 20 by a flexible capillary tube 21, and the diaphragm chamber, tube and bulb are filled with a thermostatic liquid. It will be understood that an increase in temperature at the bulb 20 will force liquid through the tube 21 into the diaphragm chamber to raise the central portion of the diaphragm 19. 7

A pair of soap switches 25 and 26 of the type disclosed in McGall 1,960,020 are secured to frame 10 by screws 28 and are acutated by the thermostatic element -by a mechanism to be described below. The switches 25 and 26 have actuating plungers 30 and 31 which actuate the switches between two operative positions depending upon the position of the plungers 30, 31. It will beu nderstood that the force required to depress thep lungers 30, 31 to 3,050,600 Patented Aug. 21, 1962 spaced pivots, one located on each side of the lever 38 to establish a stable pivotal axis for the lever. The lefthand end of the lever 38 extends beneath a nut 43 which is in screw threaded engagement with a rod 45 whose lower end is guided by an opening in the frame 10. The bottom of the rod 45 is in abutting engagement with the diaphragm 19. The nut 43 has a cylindrical upper portion which is guided in an opening in the top portion 13 of the frame 10. It will be seen that both the nut 43 and the rod 45 may be rotated and moved axially in the frame 10. On an increase in temperature the diaphragm 19 will be raised to raise the rod 45 and the nut 43 which will in turn raise the left hand end of the lever 38. A decrease in temperature will of course lower the left hand end of lever 38.

The control point of the device may be adjusted by rotating a dial 47 which is staked to the upper end of the rod 45 to change the distance between the diaphragm 19 and the lower surface of the nut 43.

The bottom end of the rod 45 is not attached to the diaphragm 19 but is merely in abutting relation thereto and to cause the rod 45 to follow the diaphragm a spring 52 is provided to bias the nut 43 and rod 45 downwardly. The top end of spring 52 acts against the frame top 13 and the bottom end acts on a collar 54 on nut 43. Collar 54 prevents nut 43 from freely rotating in the frame but permits rotation of nut 43 for calibration purposes.

With the bulb 20 exposed to the temperature at which it is desired to have the switches operate, the dial 47, and thus rod 45, is rotated until the switches operate. Dial 47 and nut 43 are then rotated together until the appropriate reading on the dial is aligned with an indicator marker. The calibration is explained in detail in the Kautz Patent 2,748,225, issued May 29, 1956.

A resilient rectangular plate 60 is attached to the right hand of lever 38 by suitable means such as rivets 61. The right hand end of resilient plate 60 cooperates .with the actuating plungers 30, 31 of the snap switches 25, 26. The snap switches 25, 26 are so mounted in the frame 10 that their actuating plungers 30, 31 are disposed in a line parallel to the pivotal axis of lever 38.

Upon an increase in temperature the fluid in capsule 20 expands forcing diaphragm 19 and rod 45 upward which causes lever 38 to rotate clockwise, this permits resilient plate 60 to move away from the switches 25, 26 and releases the actuator plungers 30, 31. As the actuating plungers 30, 31 are being released one switch will snap (due to the small differences in characteristics of the two switches) and increase the force from the plungers 30, 31 on plate 60 and cause further movement of the plate causing the other switch to snap. Therefore as one switch snaps the other does also, practically simultaneously and the possibility of a temperature rise that will actuate one switch and not the other has been eliminated. Conversely, on a temperature fall the fluid in capsule 20 will contract allowing spring 52 to move rod 45 and diaphragm 19 downward with a resulting counterclockwise movement of lever 38. This will cause plate 60 to move upward pushing actuator plungers 30, 31 of switches 25, 26 in. As plungers 30, 31 are being pushed inward one of the switches will snap reducing the restraining force of the plunger on the plate 60 of that switch. That portion of the upward force of plate 60 is then transferred to the other plunger causing the other switch to snap also. Again as one switch snaps the other does also practically simultaneously and the possibility of a temperature fall that will actuate one switch and not the other has been eliminated.

As shown in the modification of FIGURE 3, abutments 62, 63 may be provided on plate 60 for cooperation with plungers 30, 31. Abutment 63 is shown as fixed while abutment 62 is shown as a screw threaded in plate 60. By adjusting the position of screw 62 in plate 60 simultaneous snap action is facilitated.

While we have shown embodiments of our invention utilizing a solid fill temperature sensing element and a particular control point setting arrangement, we do not intend to limit our invention to these embodiments but only to limit our invention as described in the appended claims.

We claim:

1. In switching apparatus, at least two switches to be actuated substantially simultaneously, each of said switches including a snap switch andan actuator which, upon the application of sufiicient force thereto causes the switch to snap and which will retain the switch in its snapped position with the application of less force thereto than is required to snap the switch, a non-resilient condition responsive means, mechanical actuating means including a pivoted lever operatively connected to said condition responsive means at a predetermined area of said lever in such a manner that the position of said lever has a fixed relation to the position assumed by said condition respom sive means, said lever having a switch operating portion engaging the actuators of said snap switches, said portion being carried by and resiliently connected with the main portion of said lever to which said condition responsive means is connected, with the points of engagement of said switch operating portion with said actuator lying on a line sufiiciently spaced resiliently from said predetermined area of said lever at which said condition responsive means is connected that the resiliency therebetween is suificient that upon said main portion of said lever assuming a position in which sutficient force is applied to said switch operating portion of said lever to operate any one of said switches, the resilient force between the main and switch operating portions of the lever will cause the simultaneous operation of any other of said snap switches due to the operation of the first switch resulting in a greater portion of the resilient force being available for operation of the remaining switch or switches.

2. In switching apparatus, at least two switches to be actuated substantially simultaneously, each of said switches including a snap switch and an actuator which, upon the application of sufficient force thereto, causes the switch to snap and which will retain the switch in its snapped position with the application of less force thereto than is required to snap the switch, a non'resilient condition responsive means, mechanical actuating means including a pivoted lever operatively connected to said condition responsive means at a predetermined area of said lever in such a manner that the position of said lever has a fixed relation to the position assumed by said condition responsive means, a leaf spring secured to said lever and engaging the actuators of said snap switches at points lying on a line sufiiciently spaced from the predetermined area of said lever at which said condition responsive means is operatively connected that the resiliency of said leaf spring therebetween is sufiicient that upon said lever assuming a position in which suflicient resilient force is built up into said leaf spring to operate any one of said switches, the leaf spring will cause simultaneous operation of any other of said snap switches due to the operation of the first switch resulting in a greater portion of the resilient force of said leaf spring being available for operation of the remaining switch or switches.

References Cited in the file of this patent UNITED STATES PATENTS 2,200,657 Shaw May 14, 1940 2,289,882 Meyers July 14, 1942 2,373,042 Martindell Apr. 3, 1945 2,404,633 Hausler July 23, 1946 2,429,440 White Oct. 21, 1947 2,517,487 Griffith Aug. 1, 1950 2,551,479 Wallace May 1, 1951 2,578,340 De Lancey Dec. ll, 1951 2,682,590 Roberson June 29, 1954 2,748,225 Kautz May 29, 1956 FOREIGN PATENTS 626,414 Germany Oct. 12, 1934 

